| Yes - Motor Oil DOES Break Down | | | | Only the molecules that are useful to the |
| First off, all oil breaks down. That generally will | | | | purposes of lubrication and cooling are present |
| include basestocks and additives (actually SOME | | | | within the oil, and only the molecule size that is |
| additives are really "used up" rather than broken | | | | desired for the particular viscosity being |
| down - but that's getting a little picky). Without | | | | manufactured. |
| focusing on performance characteristics, the most | | | | Therefore, even if a synthetic oil does burn a |
| significant difference from one oil to another is | | | | little, the remaining oil has the same chemical |
| how quickly breakdown occurs. Although there | | | | characteristics that it had before the burn off. |
| are many factors that contribute to the | | | | There are no smaller molecules to burn-off and |
| breakdown of an oil, temperature is one of the | | | | no heavier molecules to leave behind. No oil |
| most important. Depletion and decreased | | | | thickening. No "heating blanket" effect. |
| effectiveness of oil additives is also important, but | | | | Moreover, synthetics contain few, if any, |
| that will be discussed in another article. | | | | contaminants as compared with petroleum oils |
| Petroleum oil begins to break-down almost | | | | since they are not a refined product. As a result, |
| immediately. A high quality synthetic, on the other | | | | if oil burn-off does occur, there are few, if any, |
| hand, can last for many thousands of miles | | | | contaminants left behind to leave sludge and |
| without any significant reduction in performance | | | | deposits on engine surfaces. Obviously, this leads |
| or protection characteristics. Synthetics designed | | | | to a cleaner burning, more fuel efficient engine. |
| from the right combination of basestocks and | | | | In addition, because the molecule sizes are so |
| additives can last indefinitely with the right filtration | | | | uniform in a synthetic oil and there is no "heating |
| system. | | | | blanket" effect, synthetics do a much better job |
| Oil Breakdown: Heat Tolerance | | | | of "cooling" engine components during operation. A |
| As alluded to above, the first major difference | | | | cooler running engine means longer engine life. |
| between petroleum and synthetic oil is heat | | | | AND, oil temps will often be 10 to 30 degrees |
| tolerance. Flash point is a technical specification | | | | cooler than with petroleum oils because the heat |
| referenced by most oil manufacturers which is an | | | | dissipates so much better with a synthetic. Cooler |
| indicator of heat tolerance. | | | | running oil means longer oil life and better |
| The lower the flash point of an oil the greater | | | | protection. |
| tendency for that oil to suffer vaporization loss at | | | | Oil Breakdown: The "Arctic Freeze" |
| high temperatures and to burn off on hot cylinder | | | | This is an issue that some people really don't think |
| walls and pistons. This leads to oil thickening and | | | | about when it comes to oil change intervals. Most |
| deposit build-up on critical engine components. | | | | people understand that at cold temperatures, an |
| So, the higher the flash point the better. 400 | | | | oil tends to thicken up, and many people know |
| degrees F, in my opinion, is the absolute MINIMUM | | | | that synthetics do a better job of staying fluid. |
| to prevent possible high consumption and oil | | | | However, many people don't realize WHY |
| thickening due to burn-off. Higher would definitely | | | | petroleum oils tend to thicken up. More |
| be better. | | | | importantly, though, they don't realize that this |
| Today's engines are expected to put out more | | | | thickening process can wreak havoc on not only |
| power from a smaller size and with less oil than | | | | their engine, but also their oil. |
| engines of the past. Therefore, the engines run | | | | You see, because most petroleum oils contain |
| much hotter than they used to. That puts an | | | | paraffins (wax), they tend to thicken up |
| increased burden on the oil. Synthetics are up to | | | | considerably in cold temperatures. Pour point |
| the task. Petroleum oils are better than they used | | | | depressant additives are used to help keep the oil |
| to be, but can still be a little overmatched. | | | | from thickening too much due to these waxy |
| Nevertheless, even though synthetics are MUCH | | | | contaminants - they keep the wax molecules |
| less prone to burn-off than are petroleum oils, | | | | from crystallizing together. |
| there can still be a small amount of burn-off | | | | In areas where the temperature remains below |
| during extremely high temperature operation. | | | | zero for any period of time, these additives are |
| Oil Breakdown: Motor Oil "Burn Off" | | | | used up very quickly. As a result, the oil begins to |
| Since some motor oil "burn off" will occur whether | | | | flow less easily in cold weather temperatures as |
| using synthetic or petroleum oil, it becomes | | | | the paraffins crystallize. Of course, the result is |
| important to discuss the manner in which | | | | harder cold starts and tremendously increased |
| petroleum and synthetic oils burn off. Because it is | | | | engine wear. Thus, the oil must be changed in |
| a refined product and the refining process can | | | | order to provide the cold weather engine |
| only do so much, petroleum oil molecules are of | | | | protection which is necessary. |
| varying sizes (the very smallest and largest of | | | | Synthetic oils, on the other hand, contain no |
| which are removed during the refining process - | | | | paraffins. Therefore, they need little or no additive |
| what is left is a smaller range of molecular sizes, | | | | to help with cold temperature operation. |
| but there is still significant variance in molecular | | | | Moreover, even without the additives, synthetics |
| size from one to another). Hence, as a petroleum | | | | flow at far lower temperatures than petroleum |
| oil heats up, the smaller molecules begin to burn | | | | oils. For instance, most 5w30 petroleum oils have |
| off faster and easier than the larger molecules. | | | | pour points of about -30 to -40 degrees F. Many |
| Moreover, some of those smaller molecules are | | | | synthetic oils, without any pour point depressants |
| actually contaminants that were left behind from | | | | at all, have pour points below -50 degrees F. |
| the refining process. You see, when crude oil | | | | That's a big difference. |
| comes out of the ground it is a conglomerate of | | | | Since synthetics contain little or no additives to aid |
| many different molecule types, a large portion of | | | | with cold temperature flow, synthetics maintain |
| which are not useful for lubrication purposes at all. | | | | their cold temperature flow characteristics for a |
| The refining process is designed to remove as | | | | long period of time. Additive depletion is not a |
| much of those contaminant molecules as possible, | | | | factor in the cold temperature flow of synthetic |
| but only so much can be done without raising the | | | | oils. And, as was indicated earlier in this article, |
| cost considerably. | | | | synthetics do not thicken due to burn-off. So, this |
| As all of these smaller molecules burn, deposits | | | | is not a factor in cold temperature flow either. Of |
| and sludge are left behind to coat the inside of | | | | course, the obvious result is that you don't need |
| your engine which, obviously, reduces the | | | | to change synthetic oil as often to regain |
| efficiency of your engine and can also lead to | | | | adequate cold temperature flow. |
| greater heat build-up in your engine. Anytime heat | | | | Another part of cold weather driving that is |
| increases beyond what is normal for an engine, | | | | extremely tough on an oil is condensation. |
| longevity will suffer. | | | | Because it is so cold, it takes a fairly long drive to |
| == Need A Heating Blanket for Your Engine? | | | | get the engine warm enough to burn off the |
| Obviously, that would be silly, but, in some | | | | condensation that occurs inside the engine. As a |
| respects this is exactly what petroleum oils create | | | | result, vehicles routinely driven short distances in |
| inside your engine. You see, the larger molecules | | | | cold weather will build up condensation within the |
| within your oil do not flow nearly as easily as the | | | | oil. If left to do its dirty work, this build up of |
| smaller molecules do (consider the difference in | | | | water would cause acids to be created within the |
| "pourability" of a heavy weight oil vs a light weight | | | | oil and corrosion would begin within your engine. |
| oil). Because of this, the larger molecules tend to | | | | So, there are additives in the oil which are |
| be pushed to the "outside" of the oil stream, | | | | designed to combat these acids. Synthetics |
| collecting at the surface of your engine | | | | contain higher quality and a higher quantity of |
| components while the smaller molecules flow | | | | these additives in order to properly neutralize |
| down the center of the oil stream between the | | | | these acids for a longer period of time. These |
| larger molecules. | | | | additives do deplete over time, but it takes longer |
| Thus, the larger molecules tend to "blanket" the | | | | with synthetic oils than with petroleum oils. And, if |
| components of your engine, trapping the heat | | | | you're purchasing a synthetic designed specifically |
| there as opposed to pulling the heat away into | | | | for severely extended oil drains, you'll find an |
| the oil stream. Of course, this only exacerbates | | | | even stronger acid fighting additive package. |
| the heat problem as friction builds-up. As smaller | | | | Don't Let Oil Breakdown Happen to You |
| molecules within the oil burn off, the larger, | | | | Obviously, you can't TOTALLY eliminate oil |
| heavier petroleum oil molecules are all that is left | | | | breakdown, but there are things you can do to to |
| to protect the engine. This makes the "heating | | | | minimize it. Certainly, one of the simplest ways to |
| blanket" effect even worse. | | | | avoid the negative effects of oil breakdown is to |
| In contrast, synthetic oils, because they are not | | | | simply keep your oil drains conservatively short. |
| refined or purified from crude oil, but rather are | | | | However, if you're willing to think outside the box |
| designed within a lab for lubrication purposes, are | | | | a bit you might just find some better and more |
| comprised of molecules of uniform size and shape. | | | | cost effective lubrication and filtration solutions. |